Linux Network Configuration Settings

Before continuing, it is worth checking that the network
interface card is configured as expected during the
initial setup of each SN, because it is harder to debug
these problems later when such configuration problems
show up under load.

Use the following command to determine which network
interface is being used to access a particular subnet on
each host. This command is particularly useful for
machines with multiple NICs:

Use the following command to get information about the
network speed. Note that this command requires sudo:

$ sudo ethtool eth0 | grep Speed
Speed: 1000Mb/s

You may want to consider using 10 gigabit Ethernet, or
other fast network implementations, to improve
performance for large clusters.

Server Socket Backlog

The typical default maximum server socket backlog,
typically set at 128, is too small for server style
loads. It should be at least 1K for server
applications and even a 10K value is not
unreasonable for large stores.

Set the net.core.somaxconn
property in sysctl.conf to
modify this value.

Isolating HA Network Traffic

If the machine has multiple network interfaces, you
can configure Oracle NoSQL Database to isolate HA replication
traffic on one interface, while client request
traffic uses another interface. Use the
-hahost parameter to the
makebootconfig command to specify
the interface to be used by HA as in the example
below:

In this example, all client requests will use the
interface associated with sn10.example.com, while HA
traffic will use the interface associated with
sn10-ha.example.com.

Receive Packet Steering

When multiple RNs are located on a machine with a
single queue network device, enabling Receive Packet
Steering (RPS) can help performance by distributing
the CPU load associated with packet processing (soft
interrupt handling) across multiple cores.
Multi-queue NICs provide such support directly and
do not need to have RPS enabled.

Note that this tuning advice is particularly
appropriate for customers using Oracle Big Data
Appliance.

You can determine whether a NIC is multi-queue by
using the following command: